INNERVATION OF INTEGUMENT OF CHIROPTERA 319 



approaching hairs the nerve may divide, one or two branches 

 going to a follicle, the others passing out to the epidermis (figs. 

 8, 9, fe). By far the greatest number of the nerves in question 

 are distributed in the first way. The numerous fibers form a 

 veritable network, which might justly be termed a nerve layer, 

 but which for simplicity is not so considered by the present 

 writer. 



As to nerve endings on the hair, it may be said that they occur 

 at three different levels and in three separate layers of the follicle : 

 (1) A superficial nerve ring situated above the orifices of the se- 

 baceous glands and giving off nerve threads in the connective 

 tissue sheath (fig. 9, sn); (2) Fine varicose or flattened nerve 

 fibrils which lie immediately below the sebaceous glands, and 

 end on the hyaline membrane parallel to the long axis of the 

 hair (fig. 9, eh) ; (3) Nerve fibrils at the level of the lower third 

 of the follicle, which take a horizontal position in the outer root 

 sheath (fig. 9, eo). A further consideration of these types of nerve 

 endings follows. 



1. Superficial nerve ring. Medullated nerve fibers approach 

 the hair above the opening of the sebaceous glands. At the 

 outer border of the connective sheath, they divide, spreading 

 around the follicle and forming a loose ring of from two to six or 

 more fibers. From the ring are given off non-medullated fibrils, 

 some of which are interwoven into a delicate network, while others 

 appear to end freely in the connective tissue sheath of the follicle. 

 This ring doubtless corresponds to the "broadly meshed network 

 resembling a ring" described by Sabussow ('10) above the se- 

 baceous glands. As is seen in figure 9, /, the non-medullated 

 fibrils show no tendency to pass downward to a nerve ring below. 



2. Varicose or flattened nerve fibrils. Immediately below the 

 sebaceous glands medullated nerve fibers, chiefly of type (a), 

 enter the region of the hair follicle, penetrate the connective 

 tissue layers, divide, losing their myelin, and encircle the hair 

 in a nerve ring. The number of fibers constituting the nerve 

 ring varies from two to eight or even more. From the inside 

 of the ring fibrils are given oft" which divide dichotomously. The 

 branched fibrils assume a position parallel to the long axis of the 



